1. Field of the Invention
The present invention relates to an ion generating apparatus including a function for determining a presence of an ion in the air, and an ion presence determining method.
2. Description of Related Art
Recently, it is well known about a technique utilizing positive (plus) ions and/or negative (minus) ions for cleaning the air in a living space. For example, an ion generating apparatus such as an air cleaner including a function for generating ions is known to contain an ion generator for generating plus and minus ions at the middle of an internal air duct, and emit the generated ions with the air to an external space of the apparatus.
When the ion concentration is about 1000-2000 per cm3 in the space into which the ions are emitted, it is possible to obtain a significant effect to eliminate bacteria, such as Serratia marcescens and Bacillus bacteria. In addition, the ions in the air not only inactivate airborne particles but also denature odorant components. Thus, the air is cleaned in the entire living space.
A general ion generator providing the effect described above applies a drive voltage, for a high voltage alternating current, at a portion between a needle electrode and a counter electrode, or a portion between a discharge electrode and a dielectric electrode, to generate the corona discharge and then to generate plus and minus ions. It is possible to enhance the ion concentration in the air with the utilization of plural ion generators.
On the other hand, if the discharge electrode is damaged by sputtering ejection due to the corona discharge because the ion generator is operated for a long period or a contaminant such as chemical compound or dust accumulatively attaches to the discharge electrode, the amount of generated ions is decreased. Thus, it is important to determine the presence of ions in the air, for notifying users of the requirement maintaining the ion generator.
For example, Patent Document 1 discloses an ion detecting apparatus and an ion generating apparatus that comprise a collecting electrode to collect ions in the air and detects (determines) the presence of ions based on the electric potential change of the collecting electrode at the beginning of ion generating operation (or at the ending of ion generating operation).    Patent Document 1: Japanese Patent Application Laid-Open No. 2007-114177